


Crawl Home To Her

by 21K1LLJ0YS



Category: Undertale (Video Game)
Genre: Alternate Universe - BeastTale (Undertale), Animalistic Sans (Undertale), Bara Sans, Beast Sans, Beasttale Sans (Undertale), F/M, Gen, Gentle Sans, Mating Bond, Not at first at least, Papyrus is a good bro, Papyrus is in the royal guard, Protectiveness, Reader is not happy with this, Sans is a good boi but V confused, Soulmates, Why is reader not happy?, gentle giant
Language: English
Status: In-Progress
Published: 2020-08-31
Updated: 2021-02-19
Packaged: 2021-03-06 20:40:28
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,281
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26205082
Author URL: https://archiveofourown.org/users/21K1LLJ0YS/pseuds/21K1LLJ0YS
Summary: After being permanently injured and becoming feral as a result, Sans is forced to live in the forest near Mt. Ebott in order to keep him from harming those around him with his animalistic tendencies. He discovers his soulmate hiking in the woods and drags the little human female back to his very comfortable and very SAFE nest to take care of her, as any good mate would.Wait, why is she crying?
Relationships: Papyrus & Sans (Undertale), Sans (Undertale)/Reader, Sans(Undertale)/OC, Sans(Undertale)/Original Character
Comments: 76
Kudos: 330





	1. It Begins

**Author's Note:**

> *Sigh* So I'm sure this isn't what any of you wanted from me. I'm sure you'd rather I update I'll Keep You Safe or Newcomers or even Heat of the Moment. Also, I know that this concept has been done before, but I honestly don't really care. I'm mostly writing this for me, but if you enjoy it along the way, then that's just a bonus!

He liked to stalk through the woods to see if he could sneak past the heightened senses of the animals which lived there. Stealth was never his strong-suit, being neither narrow nor light on his feet. His magic could teleport him when necessary, but he only used it when hunting particularly keen prey. He remembered teaching his little brother how to hunt. Papyrus was even less stealthy than himself and had broken down into tears many times out of frustration. Sans remembered how much he hated seeing his little brother cry and every time, he pulled the younger skeleton Beast back to their shared nest to cuddle up and provide comfort. This was many years ago in the Underground, when Papyrus was smaller than Sans. As time went on, the younger Beast grew to be absolutely massive in size, though he kept his child-like attitude and innocence. Sans himself was huge, reaching 7 feet in height when standing on 2 legs, but his brother towered over him at 9 feet tall. The brothers were truly a sight to behold as Beast monsters are fairly rare. 

When the kid came and freed them all, Beast monsters had the hardest time above ground. Their size and animalistic tendencies made them particularly frightening to humans, who only saw their stature, sharp teeth and serpent-like tails. In reality, Beasts are similar to any other monster, the only difference was an increase in instinctual behavior, which was typically not difficult to control. However, this reliance on instincts ingrained in their souls could become dangerous in the wrong circumstances, necessitating isolation and constant monitoring for the safety of humans or monsters in the area. 

It just so happens that one of these wrong circumstances befell poor Sans when he was shot in the skull by a human who was trying to attack Papyrus. The man was part of a protest against monsters soon after the beings had emerged from under Mt. Ebbot and Papyrus had just been walking past with his head bowed. Sans saw the hateful human draw a gun and had teleported himself in front of his baby brother with no hesitation, taking the bullet himself and shattering one side of his skull permanently. Any extreme injury would trigger sole control of the animalistic side of a Beast’s brain, but typically they would return to normal when they healed. 

This injury to Sans’s skull would never heal. 

When the Beast finally woke up after weeks of unconsciousness, he snarled and lunged at anyone who came close to him, only registering pain and unfamiliar surroundings and scents. Papyrus was the only one who could get near him and even though the giant bubbly Beast wanted nothing more than for his older brother to return to normal, he knew deep down that it would never happen. 

It took a very tense month of care at the monster clinic that had been hastily erected for the pain in Sans’ skull to ebb, but as soon as he was cleared, Papyrus got them both out of there. The younger Beast had fleeting hope that Sans would be able to stay in their new house, but after many instances of claw-marked drywall, destroyed appliances, and neighbors cats being eaten, he decided to do what was best for Sans. 

He needed to be away from people where he could do no harm and where he could run free and fulfil what his instincts were demanding of him. Hunt, eat, make a nest, sleep. So, Papyrus brought his brother to the wide swath of forest that would become the older Beast’s home. That day, the two stalked through the woods just like they had in the Underground. They found a cliff face on the side of a mountain that had a lovely deep cave high above the ground. It was a simple matter for the Beasts to use their powerful legs to leap into the air and climb the rest of the way with their claws digging into the rock. The floor of the cave was soft and sandy, the perfect place for a nest, and Papyrus could try to fool himself into thinking that he wasn’t heartbroken about leaving his injured brother alone here. He would have stayed with Sans, but as a prominent member of the Royal Guard, he was desperately needed to keep the peace. As the sun began to set, the two Beasts built a lovely soft nest in the back of the cave using the heaps of blankets and furs that Papyrus had brought with him. They smelled like the brothers and Papyrus hoped that the familiar scent would help Sans adjust to his new surroundings. 

Sans had mostly been moving about on all fours since his injury as Beasts typically would while hunting, so as Papyrus prepared to leave, he crouched down to get at eye level with his brother. Suddenly, it all seemed too real to the young skeleton. He hated himself for leaving Sans here alone, it felt like he was abandoning the only family he had, even though he planned on visiting very often. Magical tears gathered in the corners of Papyrus’s eye sockets, but the large Beast was startled to hear a soft grumbling purr from the feral monster in front of him. In typical animalistic fashion, Sans tried to lap away his brother’s tears with his glowing red tongue and this dog-like behavior made Papyrus laugh as he pushed his big brother’s face away. 

Taking a deep breath, Papyrus reluctantly turned away to leave the comfortable cave that was his brother’s new home, but turned back around to face Sans saying, “I WILL RETURN, BROTHER. YOU’LL BE SAFE HERE, BUT I WILL SEE YOU SOON!” 

Papyrus returned to the cave one week later with another arm full of blankets and furs to bring more of his scent into his brother’s nest, but as he approached, another scent filtered through his snout. 

There was a human female in Sans’s cave.

And she smelled extremely upset.


	2. The Finding

**Summary for the Chapter:**

> Here's what happens when Papyrus leaves a feral Sans unattended

It had been a rough few days for the feral skeleton. He was used to his brother’s constant presence and its absence left a gaping hole in his soul that mirrored the jagged cavity in his skull. Normally Beast monsters are solitary creatures, but when they do form packs, they bond for life and are seldom happy while apart from their pack-members. 

To say that Sans was forlorn would be an exaggeration, but to say that he wasn’t upset would be a lie. He was quickly able to brush up on his hunting skills, which had gotten rusty from disuse in the last few months above ground, devouring an entire full-grown deer by himself. With his appetite sated for the next few days, Sans found himself curled up in his new nest, which didn’t smell nearly enough like home for his liking, wuffling sadly. He wasn’t really aware of the changes in his personality. Memories of the massive metal structure in the Underground known as the Core and the multi-dimensional Barrier were corroded down into smells and urges that were associated with these memories. Physics meant nothing to a feral. All that Sans knew was the bond that he had with his brother and the smells of the forest around him. Life was simpler than it had ever been.

That is, until he smelled her. 

Sans’s massive head jerked up from where it had been resting on the edge of his nest. The white dots of his pupils dilated to the size of a fist and his boney nostrils flared as his soul keened at the scent of a human female. 

This wasn’t just any human female, Sans had never had any sort of instinctual reaction towards any human beyond the urge to snarl them away from Papyrus.

No, this was his soulmate. 

She smelled like plums and vanilla and Sans’s mouth watered when the scent hit his snout. 

She smelled happy. 

He was already up and leaping out of the mouth of his den, landing on the freshly damp forest floor 20 feet below. The claws of his hind legs dug furrows into the soft ground in his haste to get to his soulmate. She was near, he could tell by the intensity of her scent. 

Now, if Sans had not been feral, he still would have smelled his soulmate and been drawn to her, but he certainly would not have sprinted through the trees on all fours and leapt directly at this poor unsuspecting human woman, tackling her to the ground. Unfortunately, he was feral. And unfortunately, feral Beast monsters historically have no concept of a polite introduction, so that is exactly what he did. 

The woman didn’t even have time to shriek in surprise as a massive skeleton creature dove at her from between the dense foliage that she had been hiking through, gripping her against his chest and curling around her to take the impact of their landing. Completely caught off guard, though not hurt at all, the woman stared up with wide eyes at the pale monstrous head that was looming over her. She had met monsters before, of course, but never one as massive as this one, and would never have suspected that one of them would behave so aggressively. 

What exactly is one supposed to think in a situation like this?

“Oh God, this thing is going to eat me” comes to mind, as does “I would have preferred a bear”

The intense gaze that this creature was leveling at her certainly didn’t imply that this encounter would end well, though the human couldn’t have known that Sans’s eyelights were staring at her with pure adoration, not intent to kill.

Sans was so happy. So damn happy. His soul was vibrating with his excitement. He had found the one his very being craved, the one that he would protect and care for above all else. He nuzzled his snout against her soft little throat and purred, so thrilled to take her back to his nest and bond with her. 

His happiness wouldn’t last long. 

Typically, if a huge, clearly carnivorous creature starts to make a sound that could be a growl and puts extremely sharp teeth near a human’s jugular, that human is going to assume the worst.

As most people would, she started screaming. 

Ohh… Sans didn’t like that. What was once plums and vanilla turned sour like spoiled milk and his soul recognized this as the stench of his mate’s fear. 

To say he was confused and alarmed would be an understatement.

What in the world could possibly be wrong? In Sans’s mind, the only thing that his little mate should have been feeling was joy.

To continue what would be a seemingly endless series of misunderstandings, Sans decided that something in the immediate vicinity must be upsetting his mate, so of course the only thing to do was to get her out of the area to somewhere safe. 

This involved clutching the panicking woman to his ribs with one arm and loping at full speed back to Sans’s den. This wasn’t the easiest thing to do as for some reason, his soulmate wouldn’t stop squirming in his arms. Spoiled milk started to mix with something that was like campfire smoke. 

Anger, Sans’s soul provided. 

Well, he could make it better when they were curled up together in his nest.

Their nest.

The woman was not having the best time, which shouldn’t really be surprising. Part of her was still convinced that this huge monster was planning on eating her, but most of her thought processes were focused on trying not to throw up. She really didn’t appreciate this strange creature’s method of transport.

Finally, the pair reached the base of the cliff which held Sans’s den. The Beast took a moment to nuzzle his mate’s hair and purred soothingly before adjusting his grip on her and leaping up to the mouth of his cave. 

Oh GOD she was going to be sick. He was going to drop her oh my God he was going to drop her pleasepleasepleasenononononono.

Without another moment’s hesitation after landing perfectly safely on the sandy floor of his den, Sans carried his mate, who seemed to be breathing very strangely, to the back of the cave where the mountain of blankets and furs lay. He rumbled softly as he laid her down at the base and secured her back against his chest before she could squirm away. His long dexterous tail wrapped around her calf and he delighted in her diminutive stature. He was curled around her such that almost her entire body was touching him. 

Surely her fear and anger scents would settle now that she was safe in their nest with him stroking his tongue across her throat comfortingly. 

“Oh”, the human thought, “I’m so fucked.”

**Notes for the Chapter:**

> Hey I hate myself for being so inspired to write this (literally JUST updated yesterday) but having so much trouble with I'll Keep You Safe. Maybe it's because this story already has established characters?


	3. The Revealing

**Summary for the Chapter:**

> Papyrus discovers the human and Sans.

**Notes for the Chapter:**

> Ayyy look who updated a work for once! Also, if you've been reading my I'll Keep You Safe series, I just posted a chapter last night! Go read it if you feel like it!

Papyrus dropped the furs and blankets he was holding, got onto all fours, and sprinted towards his brother’s cave. The scent of human anxiety and Sans’ worry made Papyrus’ magic thrum in concern. He wasn’t just concerned for the human, after all, he would have smelled blood if she had been injured, but he was mostly worried about his newly-feral brother and the massive amounts of trouble that Sans would be in. What was he thinking? He should have stayed here with Sans until the older skeleton monster got acclimated to his new home! In fact, maybe they should have stayed together permanently. As Papyrus reached the base of the cliff that housed Sans’ cave, he could hear a faint woman’s voice and, more clearly, a rumbling purr. 

Papyrus leapt into the mouth of the cave, intent on apologizing profusely to the human his brother had unintentionally kidnapped, getting her back to civilization, and delivering a sound scolding to his older brother, who no doubt would have no idea what he was saying. 

Papyrus had never been scared of his brother before, but when the comforting purr that had been vibrating the air in the cave turned into an aggressive snarl, a coil of fear spiked through Papyrus’ ribcage. This feeling was amplified when he saw the human-monster pair in Sans’ nest. The big feral monster was crouching over a young woman, who Papyrus could barely make out as Sans was covering most of her body with his own. What caused fear to jerk through the younger monster was the sight of Sans’ right eyelight completely extinguished, and his left blazing with red fire, puffs of crimson magic leaking through his clenched grin. 

The Beast monster was staring at Papyrus with an unmistakable threat that he didn’t need words to express. 

If you come closer, I will dust you. 

Thinking quickly, Papyrus realized that he had to do something that he had never done before, or his brother would make good on his silent promise. 

Still on all fours from his leap into the cave and not daring to speak, he lowered himself further to the sandy floor with slow, careful motions, then rolled onto his side, belly up towards his older brother. 

A sign of submission. 

Sans’ unnerving stare softened slightly and his growl quieted, but the red flare of magic still infected his eye socket. Seemingly reluctantly, he exited the nest, still hiding the woman from view and approached the taller skeleton. 

When Sans’ wide pale skull was inches away from Papyrus’ own and his boney nostrils flared, the magic in his flaring socket died down to the large red dot that had been normal ever since the attack. 

Then a slobbery red tongue appeared, swiping across Papyrus’ face.

“SANS! DON’T BE DISGUSTING!” Papyrus yelped, pushing Sans’ face away from his own, though he was truly relieved to not be under his brother’s withering stare anymore. He slowly rose back up to his hind legs, warily, so not to trigger another defensive episode from Sans, almost hitting the crown of his skull on the ceiling of the cave. “I DON’T KNOW WHAT HAS GOTTEN INTO YOU, BUT YOU NEED TO BE SERIOUS FOR A MOMENT!” 

Papyrus looked back at the human in the nest, only to find that she wasn’t lying where she had been underneath Sans before. It took a moment for his eyelights to adjust to the darkness of the cave, but he finally spotted her standing with her back to the far wall, as far away from the two monsters as possible, chest heaving and eyes wide and panicked. 

“OH,” Papyrus said, before forcing his booming voice into a lower decibel level, “Uhm… Hello Human! I Am The Great Papyrus!” Shockingly, the human didn’t seem awe-inspired, but rather continued to look terrified. “Ehem… My Brother Sans Here Seems To Have Taken Some Liberties With Your Freedom, Tiny Human!” 

“You could say that,” the woman said warily, now looking more skeptical than petrified. Sans uttered a happy churr at the sound of her voice. 

“Well… Ehem... You See, My Brother Was Injured By Some Humans About A Month Ago, And Ever Since Then, He Has Been What We Call ‘Feral’” Papyrus was wringing the bones of his hands together nervously, trying his best to both be cordial and convince the woman to not press charges. It wouldn’t do to have this human tell the authorities that a dangerous monster had taken her hostage. Human-Monster relations were already strained as it was. “He Didn’t Mean To Scare You I Don’t Think. In Fact, I’m Really Not Sure Why He Brought You Here In The First Place… BUT I’M SURE THAT HIS INTENTION WASN’T TO HURT YOU,” this last part was almost shrieked and the sound made the human wince, prompting Sans to swipe at the taller skeleton’s shin bones and growl. 

“I was just hiking, literally just walking through the forest when… Sans? Tackled me and dragged me here!” Once the woman started talking, she couldn’t seem to stop. “He scared the shit out of me! I thought he was gonna eat me and he kept making these sounds and when he brought me back here, he just pinned me and wouldn’t let me go and… and,” tears were building in the human’s eyes, “And I just want to go HOME!” she cried out and buried her face in her hands as her shoulders shook, clearly the day had been too much for her. ''

The taller Beast monster felt like a failure, almost able to see the police lights flashing in their future. He had failed as a brother. He should have done something to prevent this awful situation from happening. Who knows what would happen to Sans now that he had attacked a human! 

As he was lost in his worried thoughts, Papyrus almost missed Sans moving towards the human out of the corner of his eyesocket, but there is no way he could have missed what the big skeleton did next. 

Like an oversized cat, the feral Beast monster approached the distraught human and pressed his massive skull into the flesh of her cloth-covered abdomen, gently purring as he nuzzled her. After several minutes of Papyrus awkwardly watching his big brother attempt to comfort a weeping woman, whose sobs had died down into hiccups, hardly able to believe that this was the same monster who was so aloof with every other human, a lightbulb went off in Papyrus's skull. He couldn't believe that he had missed it before.

“Um… Human?” 

The woman finally took her hands away from her tear-streaked face, though she made sure not to touch the skull that was nestled against her, and looked at the tall Beast monster. 

“I Think You Might Be My Brother’s Soulmate”

**Author's Note:**

> Well, if you'd like me to continue let me know down in the comments what you liked about it. If you hated it, that's cool too, roast me down below.


End file.
